nf_conntrack_core.c revision 8fea97ec1772bbf553d89187340ef624d548e115
1/* Connection state tracking for netfilter. This is separated from, 2 but required by, the NAT layer; it can also be used by an iptables 3 extension. */ 4 5/* (C) 1999-2001 Paul `Rusty' Russell 6 * (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org> 7 * (C) 2003,2004 USAGI/WIDE Project <http://www.linux-ipv6.org> 8 * 9 * This program is free software; you can redistribute it and/or modify 10 * it under the terms of the GNU General Public License version 2 as 11 * published by the Free Software Foundation. 12 */ 13 14#include <linux/types.h> 15#include <linux/netfilter.h> 16#include <linux/module.h> 17#include <linux/sched.h> 18#include <linux/skbuff.h> 19#include <linux/proc_fs.h> 20#include <linux/vmalloc.h> 21#include <linux/stddef.h> 22#include <linux/slab.h> 23#include <linux/random.h> 24#include <linux/jhash.h> 25#include <linux/err.h> 26#include <linux/percpu.h> 27#include <linux/moduleparam.h> 28#include <linux/notifier.h> 29#include <linux/kernel.h> 30#include <linux/netdevice.h> 31#include <linux/socket.h> 32#include <linux/mm.h> 33#include <linux/nsproxy.h> 34#include <linux/rculist_nulls.h> 35 36#include <net/netfilter/nf_conntrack.h> 37#include <net/netfilter/nf_conntrack_l3proto.h> 38#include <net/netfilter/nf_conntrack_l4proto.h> 39#include <net/netfilter/nf_conntrack_expect.h> 40#include <net/netfilter/nf_conntrack_helper.h> 41#include <net/netfilter/nf_conntrack_core.h> 42#include <net/netfilter/nf_conntrack_extend.h> 43#include <net/netfilter/nf_conntrack_acct.h> 44#include <net/netfilter/nf_conntrack_ecache.h> 45#include <net/netfilter/nf_nat.h> 46#include <net/netfilter/nf_nat_core.h> 47 48#define NF_CONNTRACK_VERSION "0.5.0" 49 50int (*nfnetlink_parse_nat_setup_hook)(struct nf_conn *ct, 51 enum nf_nat_manip_type manip, 52 const struct nlattr *attr) __read_mostly; 53EXPORT_SYMBOL_GPL(nfnetlink_parse_nat_setup_hook); 54 55DEFINE_SPINLOCK(nf_conntrack_lock); 56EXPORT_SYMBOL_GPL(nf_conntrack_lock); 57 58unsigned int nf_conntrack_htable_size __read_mostly; 59EXPORT_SYMBOL_GPL(nf_conntrack_htable_size); 60 61unsigned int nf_conntrack_max __read_mostly; 62EXPORT_SYMBOL_GPL(nf_conntrack_max); 63 64struct nf_conn nf_conntrack_untracked __read_mostly; 65EXPORT_SYMBOL_GPL(nf_conntrack_untracked); 66 67static int nf_conntrack_hash_rnd_initted; 68static unsigned int nf_conntrack_hash_rnd; 69 70static u_int32_t __hash_conntrack(const struct nf_conntrack_tuple *tuple, 71 unsigned int size, unsigned int rnd) 72{ 73 unsigned int n; 74 u_int32_t h; 75 76 /* The direction must be ignored, so we hash everything up to the 77 * destination ports (which is a multiple of 4) and treat the last 78 * three bytes manually. 79 */ 80 n = (sizeof(tuple->src) + sizeof(tuple->dst.u3)) / sizeof(u32); 81 h = jhash2((u32 *)tuple, n, 82 rnd ^ (((__force __u16)tuple->dst.u.all << 16) | 83 tuple->dst.protonum)); 84 85 return ((u64)h * size) >> 32; 86} 87 88static inline u_int32_t hash_conntrack(const struct net *net, 89 const struct nf_conntrack_tuple *tuple) 90{ 91 return __hash_conntrack(tuple, net->ct.htable_size, 92 nf_conntrack_hash_rnd); 93} 94 95bool 96nf_ct_get_tuple(const struct sk_buff *skb, 97 unsigned int nhoff, 98 unsigned int dataoff, 99 u_int16_t l3num, 100 u_int8_t protonum, 101 struct nf_conntrack_tuple *tuple, 102 const struct nf_conntrack_l3proto *l3proto, 103 const struct nf_conntrack_l4proto *l4proto) 104{ 105 memset(tuple, 0, sizeof(*tuple)); 106 107 tuple->src.l3num = l3num; 108 if (l3proto->pkt_to_tuple(skb, nhoff, tuple) == 0) 109 return false; 110 111 tuple->dst.protonum = protonum; 112 tuple->dst.dir = IP_CT_DIR_ORIGINAL; 113 114 return l4proto->pkt_to_tuple(skb, dataoff, tuple); 115} 116EXPORT_SYMBOL_GPL(nf_ct_get_tuple); 117 118bool nf_ct_get_tuplepr(const struct sk_buff *skb, unsigned int nhoff, 119 u_int16_t l3num, struct nf_conntrack_tuple *tuple) 120{ 121 struct nf_conntrack_l3proto *l3proto; 122 struct nf_conntrack_l4proto *l4proto; 123 unsigned int protoff; 124 u_int8_t protonum; 125 int ret; 126 127 rcu_read_lock(); 128 129 l3proto = __nf_ct_l3proto_find(l3num); 130 ret = l3proto->get_l4proto(skb, nhoff, &protoff, &protonum); 131 if (ret != NF_ACCEPT) { 132 rcu_read_unlock(); 133 return false; 134 } 135 136 l4proto = __nf_ct_l4proto_find(l3num, protonum); 137 138 ret = nf_ct_get_tuple(skb, nhoff, protoff, l3num, protonum, tuple, 139 l3proto, l4proto); 140 141 rcu_read_unlock(); 142 return ret; 143} 144EXPORT_SYMBOL_GPL(nf_ct_get_tuplepr); 145 146bool 147nf_ct_invert_tuple(struct nf_conntrack_tuple *inverse, 148 const struct nf_conntrack_tuple *orig, 149 const struct nf_conntrack_l3proto *l3proto, 150 const struct nf_conntrack_l4proto *l4proto) 151{ 152 memset(inverse, 0, sizeof(*inverse)); 153 154 inverse->src.l3num = orig->src.l3num; 155 if (l3proto->invert_tuple(inverse, orig) == 0) 156 return false; 157 158 inverse->dst.dir = !orig->dst.dir; 159 160 inverse->dst.protonum = orig->dst.protonum; 161 return l4proto->invert_tuple(inverse, orig); 162} 163EXPORT_SYMBOL_GPL(nf_ct_invert_tuple); 164 165static void 166clean_from_lists(struct nf_conn *ct) 167{ 168 pr_debug("clean_from_lists(%p)\n", ct); 169 hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode); 170 hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode); 171 172 /* Destroy all pending expectations */ 173 nf_ct_remove_expectations(ct); 174} 175 176static void 177destroy_conntrack(struct nf_conntrack *nfct) 178{ 179 struct nf_conn *ct = (struct nf_conn *)nfct; 180 struct net *net = nf_ct_net(ct); 181 struct nf_conntrack_l4proto *l4proto; 182 183 pr_debug("destroy_conntrack(%p)\n", ct); 184 NF_CT_ASSERT(atomic_read(&nfct->use) == 0); 185 NF_CT_ASSERT(!timer_pending(&ct->timeout)); 186 187 /* To make sure we don't get any weird locking issues here: 188 * destroy_conntrack() MUST NOT be called with a write lock 189 * to nf_conntrack_lock!!! -HW */ 190 rcu_read_lock(); 191 l4proto = __nf_ct_l4proto_find(nf_ct_l3num(ct), nf_ct_protonum(ct)); 192 if (l4proto && l4proto->destroy) 193 l4proto->destroy(ct); 194 195 rcu_read_unlock(); 196 197 spin_lock_bh(&nf_conntrack_lock); 198 /* Expectations will have been removed in clean_from_lists, 199 * except TFTP can create an expectation on the first packet, 200 * before connection is in the list, so we need to clean here, 201 * too. */ 202 nf_ct_remove_expectations(ct); 203 204 /* We overload first tuple to link into unconfirmed list. */ 205 if (!nf_ct_is_confirmed(ct)) { 206 BUG_ON(hlist_nulls_unhashed(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode)); 207 hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode); 208 } 209 210 NF_CT_STAT_INC(net, delete); 211 spin_unlock_bh(&nf_conntrack_lock); 212 213 if (ct->master) 214 nf_ct_put(ct->master); 215 216 pr_debug("destroy_conntrack: returning ct=%p to slab\n", ct); 217 nf_conntrack_free(ct); 218} 219 220void nf_ct_delete_from_lists(struct nf_conn *ct) 221{ 222 struct net *net = nf_ct_net(ct); 223 224 nf_ct_helper_destroy(ct); 225 spin_lock_bh(&nf_conntrack_lock); 226 /* Inside lock so preempt is disabled on module removal path. 227 * Otherwise we can get spurious warnings. */ 228 NF_CT_STAT_INC(net, delete_list); 229 clean_from_lists(ct); 230 spin_unlock_bh(&nf_conntrack_lock); 231} 232EXPORT_SYMBOL_GPL(nf_ct_delete_from_lists); 233 234static void death_by_event(unsigned long ul_conntrack) 235{ 236 struct nf_conn *ct = (void *)ul_conntrack; 237 struct net *net = nf_ct_net(ct); 238 239 if (nf_conntrack_event(IPCT_DESTROY, ct) < 0) { 240 /* bad luck, let's retry again */ 241 ct->timeout.expires = jiffies + 242 (random32() % net->ct.sysctl_events_retry_timeout); 243 add_timer(&ct->timeout); 244 return; 245 } 246 /* we've got the event delivered, now it's dying */ 247 set_bit(IPS_DYING_BIT, &ct->status); 248 spin_lock(&nf_conntrack_lock); 249 hlist_nulls_del(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode); 250 spin_unlock(&nf_conntrack_lock); 251 nf_ct_put(ct); 252} 253 254void nf_ct_insert_dying_list(struct nf_conn *ct) 255{ 256 struct net *net = nf_ct_net(ct); 257 258 /* add this conntrack to the dying list */ 259 spin_lock_bh(&nf_conntrack_lock); 260 hlist_nulls_add_head(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode, 261 &net->ct.dying); 262 spin_unlock_bh(&nf_conntrack_lock); 263 /* set a new timer to retry event delivery */ 264 setup_timer(&ct->timeout, death_by_event, (unsigned long)ct); 265 ct->timeout.expires = jiffies + 266 (random32() % net->ct.sysctl_events_retry_timeout); 267 add_timer(&ct->timeout); 268} 269EXPORT_SYMBOL_GPL(nf_ct_insert_dying_list); 270 271static void death_by_timeout(unsigned long ul_conntrack) 272{ 273 struct nf_conn *ct = (void *)ul_conntrack; 274 275 if (!test_bit(IPS_DYING_BIT, &ct->status) && 276 unlikely(nf_conntrack_event(IPCT_DESTROY, ct) < 0)) { 277 /* destroy event was not delivered */ 278 nf_ct_delete_from_lists(ct); 279 nf_ct_insert_dying_list(ct); 280 return; 281 } 282 set_bit(IPS_DYING_BIT, &ct->status); 283 nf_ct_delete_from_lists(ct); 284 nf_ct_put(ct); 285} 286 287/* 288 * Warning : 289 * - Caller must take a reference on returned object 290 * and recheck nf_ct_tuple_equal(tuple, &h->tuple) 291 * OR 292 * - Caller must lock nf_conntrack_lock before calling this function 293 */ 294struct nf_conntrack_tuple_hash * 295__nf_conntrack_find(struct net *net, const struct nf_conntrack_tuple *tuple) 296{ 297 struct nf_conntrack_tuple_hash *h; 298 struct hlist_nulls_node *n; 299 unsigned int hash = hash_conntrack(net, tuple); 300 301 /* Disable BHs the entire time since we normally need to disable them 302 * at least once for the stats anyway. 303 */ 304 local_bh_disable(); 305begin: 306 hlist_nulls_for_each_entry_rcu(h, n, &net->ct.hash[hash], hnnode) { 307 if (nf_ct_tuple_equal(tuple, &h->tuple)) { 308 NF_CT_STAT_INC(net, found); 309 local_bh_enable(); 310 return h; 311 } 312 NF_CT_STAT_INC(net, searched); 313 } 314 /* 315 * if the nulls value we got at the end of this lookup is 316 * not the expected one, we must restart lookup. 317 * We probably met an item that was moved to another chain. 318 */ 319 if (get_nulls_value(n) != hash) 320 goto begin; 321 local_bh_enable(); 322 323 return NULL; 324} 325EXPORT_SYMBOL_GPL(__nf_conntrack_find); 326 327/* Find a connection corresponding to a tuple. */ 328struct nf_conntrack_tuple_hash * 329nf_conntrack_find_get(struct net *net, const struct nf_conntrack_tuple *tuple) 330{ 331 struct nf_conntrack_tuple_hash *h; 332 struct nf_conn *ct; 333 334 rcu_read_lock(); 335begin: 336 h = __nf_conntrack_find(net, tuple); 337 if (h) { 338 ct = nf_ct_tuplehash_to_ctrack(h); 339 if (unlikely(nf_ct_is_dying(ct) || 340 !atomic_inc_not_zero(&ct->ct_general.use))) 341 h = NULL; 342 else { 343 if (unlikely(!nf_ct_tuple_equal(tuple, &h->tuple))) { 344 nf_ct_put(ct); 345 goto begin; 346 } 347 } 348 } 349 rcu_read_unlock(); 350 351 return h; 352} 353EXPORT_SYMBOL_GPL(nf_conntrack_find_get); 354 355static void __nf_conntrack_hash_insert(struct nf_conn *ct, 356 unsigned int hash, 357 unsigned int repl_hash) 358{ 359 struct net *net = nf_ct_net(ct); 360 361 hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode, 362 &net->ct.hash[hash]); 363 hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_REPLY].hnnode, 364 &net->ct.hash[repl_hash]); 365} 366 367void nf_conntrack_hash_insert(struct nf_conn *ct) 368{ 369 struct net *net = nf_ct_net(ct); 370 unsigned int hash, repl_hash; 371 372 hash = hash_conntrack(net, &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple); 373 repl_hash = hash_conntrack(net, &ct->tuplehash[IP_CT_DIR_REPLY].tuple); 374 375 __nf_conntrack_hash_insert(ct, hash, repl_hash); 376} 377EXPORT_SYMBOL_GPL(nf_conntrack_hash_insert); 378 379/* Confirm a connection given skb; places it in hash table */ 380int 381__nf_conntrack_confirm(struct sk_buff *skb) 382{ 383 unsigned int hash, repl_hash; 384 struct nf_conntrack_tuple_hash *h; 385 struct nf_conn *ct; 386 struct nf_conn_help *help; 387 struct hlist_nulls_node *n; 388 enum ip_conntrack_info ctinfo; 389 struct net *net; 390 391 ct = nf_ct_get(skb, &ctinfo); 392 net = nf_ct_net(ct); 393 394 /* ipt_REJECT uses nf_conntrack_attach to attach related 395 ICMP/TCP RST packets in other direction. Actual packet 396 which created connection will be IP_CT_NEW or for an 397 expected connection, IP_CT_RELATED. */ 398 if (CTINFO2DIR(ctinfo) != IP_CT_DIR_ORIGINAL) 399 return NF_ACCEPT; 400 401 hash = hash_conntrack(net, &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple); 402 repl_hash = hash_conntrack(net, &ct->tuplehash[IP_CT_DIR_REPLY].tuple); 403 404 /* We're not in hash table, and we refuse to set up related 405 connections for unconfirmed conns. But packet copies and 406 REJECT will give spurious warnings here. */ 407 /* NF_CT_ASSERT(atomic_read(&ct->ct_general.use) == 1); */ 408 409 /* No external references means noone else could have 410 confirmed us. */ 411 NF_CT_ASSERT(!nf_ct_is_confirmed(ct)); 412 pr_debug("Confirming conntrack %p\n", ct); 413 414 spin_lock_bh(&nf_conntrack_lock); 415 416 /* See if there's one in the list already, including reverse: 417 NAT could have grabbed it without realizing, since we're 418 not in the hash. If there is, we lost race. */ 419 hlist_nulls_for_each_entry(h, n, &net->ct.hash[hash], hnnode) 420 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple, 421 &h->tuple)) 422 goto out; 423 hlist_nulls_for_each_entry(h, n, &net->ct.hash[repl_hash], hnnode) 424 if (nf_ct_tuple_equal(&ct->tuplehash[IP_CT_DIR_REPLY].tuple, 425 &h->tuple)) 426 goto out; 427 428 /* Remove from unconfirmed list */ 429 hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode); 430 431 /* Timer relative to confirmation time, not original 432 setting time, otherwise we'd get timer wrap in 433 weird delay cases. */ 434 ct->timeout.expires += jiffies; 435 add_timer(&ct->timeout); 436 atomic_inc(&ct->ct_general.use); 437 set_bit(IPS_CONFIRMED_BIT, &ct->status); 438 439 /* Since the lookup is lockless, hash insertion must be done after 440 * starting the timer and setting the CONFIRMED bit. The RCU barriers 441 * guarantee that no other CPU can find the conntrack before the above 442 * stores are visible. 443 */ 444 __nf_conntrack_hash_insert(ct, hash, repl_hash); 445 NF_CT_STAT_INC(net, insert); 446 spin_unlock_bh(&nf_conntrack_lock); 447 448 help = nfct_help(ct); 449 if (help && help->helper) 450 nf_conntrack_event_cache(IPCT_HELPER, ct); 451 452 nf_conntrack_event_cache(master_ct(ct) ? 453 IPCT_RELATED : IPCT_NEW, ct); 454 return NF_ACCEPT; 455 456out: 457 NF_CT_STAT_INC(net, insert_failed); 458 spin_unlock_bh(&nf_conntrack_lock); 459 return NF_DROP; 460} 461EXPORT_SYMBOL_GPL(__nf_conntrack_confirm); 462 463/* Returns true if a connection correspondings to the tuple (required 464 for NAT). */ 465int 466nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple, 467 const struct nf_conn *ignored_conntrack) 468{ 469 struct net *net = nf_ct_net(ignored_conntrack); 470 struct nf_conntrack_tuple_hash *h; 471 struct hlist_nulls_node *n; 472 unsigned int hash = hash_conntrack(net, tuple); 473 474 /* Disable BHs the entire time since we need to disable them at 475 * least once for the stats anyway. 476 */ 477 rcu_read_lock_bh(); 478 hlist_nulls_for_each_entry_rcu(h, n, &net->ct.hash[hash], hnnode) { 479 if (nf_ct_tuplehash_to_ctrack(h) != ignored_conntrack && 480 nf_ct_tuple_equal(tuple, &h->tuple)) { 481 NF_CT_STAT_INC(net, found); 482 rcu_read_unlock_bh(); 483 return 1; 484 } 485 NF_CT_STAT_INC(net, searched); 486 } 487 rcu_read_unlock_bh(); 488 489 return 0; 490} 491EXPORT_SYMBOL_GPL(nf_conntrack_tuple_taken); 492 493#define NF_CT_EVICTION_RANGE 8 494 495/* There's a small race here where we may free a just-assured 496 connection. Too bad: we're in trouble anyway. */ 497static noinline int early_drop(struct net *net, unsigned int hash) 498{ 499 /* Use oldest entry, which is roughly LRU */ 500 struct nf_conntrack_tuple_hash *h; 501 struct nf_conn *ct = NULL, *tmp; 502 struct hlist_nulls_node *n; 503 unsigned int i, cnt = 0; 504 int dropped = 0; 505 506 rcu_read_lock(); 507 for (i = 0; i < net->ct.htable_size; i++) { 508 hlist_nulls_for_each_entry_rcu(h, n, &net->ct.hash[hash], 509 hnnode) { 510 tmp = nf_ct_tuplehash_to_ctrack(h); 511 if (!test_bit(IPS_ASSURED_BIT, &tmp->status)) 512 ct = tmp; 513 cnt++; 514 } 515 516 if (ct != NULL) { 517 if (likely(!nf_ct_is_dying(ct) && 518 atomic_inc_not_zero(&ct->ct_general.use))) 519 break; 520 else 521 ct = NULL; 522 } 523 524 if (cnt >= NF_CT_EVICTION_RANGE) 525 break; 526 527 hash = (hash + 1) % net->ct.htable_size; 528 } 529 rcu_read_unlock(); 530 531 if (!ct) 532 return dropped; 533 534 if (del_timer(&ct->timeout)) { 535 death_by_timeout((unsigned long)ct); 536 dropped = 1; 537 NF_CT_STAT_INC_ATOMIC(net, early_drop); 538 } 539 nf_ct_put(ct); 540 return dropped; 541} 542 543struct nf_conn *nf_conntrack_alloc(struct net *net, 544 const struct nf_conntrack_tuple *orig, 545 const struct nf_conntrack_tuple *repl, 546 gfp_t gfp) 547{ 548 struct nf_conn *ct; 549 550 if (unlikely(!nf_conntrack_hash_rnd_initted)) { 551 get_random_bytes(&nf_conntrack_hash_rnd, 552 sizeof(nf_conntrack_hash_rnd)); 553 nf_conntrack_hash_rnd_initted = 1; 554 } 555 556 /* We don't want any race condition at early drop stage */ 557 atomic_inc(&net->ct.count); 558 559 if (nf_conntrack_max && 560 unlikely(atomic_read(&net->ct.count) > nf_conntrack_max)) { 561 unsigned int hash = hash_conntrack(net, orig); 562 if (!early_drop(net, hash)) { 563 atomic_dec(&net->ct.count); 564 if (net_ratelimit()) 565 printk(KERN_WARNING 566 "nf_conntrack: table full, dropping" 567 " packet.\n"); 568 return ERR_PTR(-ENOMEM); 569 } 570 } 571 572 /* 573 * Do not use kmem_cache_zalloc(), as this cache uses 574 * SLAB_DESTROY_BY_RCU. 575 */ 576 ct = kmem_cache_alloc(net->ct.nf_conntrack_cachep, gfp); 577 if (ct == NULL) { 578 pr_debug("nf_conntrack_alloc: Can't alloc conntrack.\n"); 579 atomic_dec(&net->ct.count); 580 return ERR_PTR(-ENOMEM); 581 } 582 /* 583 * Let ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode.next 584 * and ct->tuplehash[IP_CT_DIR_REPLY].hnnode.next unchanged. 585 */ 586 memset(&ct->tuplehash[IP_CT_DIR_MAX], 0, 587 sizeof(*ct) - offsetof(struct nf_conn, tuplehash[IP_CT_DIR_MAX])); 588 spin_lock_init(&ct->lock); 589 ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple = *orig; 590 ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode.pprev = NULL; 591 ct->tuplehash[IP_CT_DIR_REPLY].tuple = *repl; 592 ct->tuplehash[IP_CT_DIR_REPLY].hnnode.pprev = NULL; 593 /* Don't set timer yet: wait for confirmation */ 594 setup_timer(&ct->timeout, death_by_timeout, (unsigned long)ct); 595#ifdef CONFIG_NET_NS 596 ct->ct_net = net; 597#endif 598 599 /* 600 * changes to lookup keys must be done before setting refcnt to 1 601 */ 602 smp_wmb(); 603 atomic_set(&ct->ct_general.use, 1); 604 return ct; 605} 606EXPORT_SYMBOL_GPL(nf_conntrack_alloc); 607 608void nf_conntrack_free(struct nf_conn *ct) 609{ 610 struct net *net = nf_ct_net(ct); 611 612 nf_ct_ext_destroy(ct); 613 atomic_dec(&net->ct.count); 614 nf_ct_ext_free(ct); 615 kmem_cache_free(net->ct.nf_conntrack_cachep, ct); 616} 617EXPORT_SYMBOL_GPL(nf_conntrack_free); 618 619/* Allocate a new conntrack: we return -ENOMEM if classification 620 failed due to stress. Otherwise it really is unclassifiable. */ 621static struct nf_conntrack_tuple_hash * 622init_conntrack(struct net *net, struct nf_conn *tmpl, 623 const struct nf_conntrack_tuple *tuple, 624 struct nf_conntrack_l3proto *l3proto, 625 struct nf_conntrack_l4proto *l4proto, 626 struct sk_buff *skb, 627 unsigned int dataoff) 628{ 629 struct nf_conn *ct; 630 struct nf_conn_help *help; 631 struct nf_conntrack_tuple repl_tuple; 632 struct nf_conntrack_ecache *ecache; 633 struct nf_conntrack_expect *exp; 634 635 if (!nf_ct_invert_tuple(&repl_tuple, tuple, l3proto, l4proto)) { 636 pr_debug("Can't invert tuple.\n"); 637 return NULL; 638 } 639 640 ct = nf_conntrack_alloc(net, tuple, &repl_tuple, GFP_ATOMIC); 641 if (IS_ERR(ct)) { 642 pr_debug("Can't allocate conntrack.\n"); 643 return (struct nf_conntrack_tuple_hash *)ct; 644 } 645 646 if (!l4proto->new(ct, skb, dataoff)) { 647 nf_conntrack_free(ct); 648 pr_debug("init conntrack: can't track with proto module\n"); 649 return NULL; 650 } 651 652 nf_ct_acct_ext_add(ct, GFP_ATOMIC); 653 654 ecache = tmpl ? nf_ct_ecache_find(tmpl) : NULL; 655 nf_ct_ecache_ext_add(ct, ecache ? ecache->ctmask : 0, 656 ecache ? ecache->expmask : 0, 657 GFP_ATOMIC); 658 659 spin_lock_bh(&nf_conntrack_lock); 660 exp = nf_ct_find_expectation(net, tuple); 661 if (exp) { 662 pr_debug("conntrack: expectation arrives ct=%p exp=%p\n", 663 ct, exp); 664 /* Welcome, Mr. Bond. We've been expecting you... */ 665 __set_bit(IPS_EXPECTED_BIT, &ct->status); 666 ct->master = exp->master; 667 if (exp->helper) { 668 help = nf_ct_helper_ext_add(ct, GFP_ATOMIC); 669 if (help) 670 rcu_assign_pointer(help->helper, exp->helper); 671 } 672 673#ifdef CONFIG_NF_CONNTRACK_MARK 674 ct->mark = exp->master->mark; 675#endif 676#ifdef CONFIG_NF_CONNTRACK_SECMARK 677 ct->secmark = exp->master->secmark; 678#endif 679 nf_conntrack_get(&ct->master->ct_general); 680 NF_CT_STAT_INC(net, expect_new); 681 } else { 682 __nf_ct_try_assign_helper(ct, tmpl, GFP_ATOMIC); 683 NF_CT_STAT_INC(net, new); 684 } 685 686 /* Overload tuple linked list to put us in unconfirmed list. */ 687 hlist_nulls_add_head_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode, 688 &net->ct.unconfirmed); 689 690 spin_unlock_bh(&nf_conntrack_lock); 691 692 if (exp) { 693 if (exp->expectfn) 694 exp->expectfn(ct, exp); 695 nf_ct_expect_put(exp); 696 } 697 698 return &ct->tuplehash[IP_CT_DIR_ORIGINAL]; 699} 700 701/* On success, returns conntrack ptr, sets skb->nfct and ctinfo */ 702static inline struct nf_conn * 703resolve_normal_ct(struct net *net, struct nf_conn *tmpl, 704 struct sk_buff *skb, 705 unsigned int dataoff, 706 u_int16_t l3num, 707 u_int8_t protonum, 708 struct nf_conntrack_l3proto *l3proto, 709 struct nf_conntrack_l4proto *l4proto, 710 int *set_reply, 711 enum ip_conntrack_info *ctinfo) 712{ 713 struct nf_conntrack_tuple tuple; 714 struct nf_conntrack_tuple_hash *h; 715 struct nf_conn *ct; 716 717 if (!nf_ct_get_tuple(skb, skb_network_offset(skb), 718 dataoff, l3num, protonum, &tuple, l3proto, 719 l4proto)) { 720 pr_debug("resolve_normal_ct: Can't get tuple\n"); 721 return NULL; 722 } 723 724 /* look for tuple match */ 725 h = nf_conntrack_find_get(net, &tuple); 726 if (!h) { 727 h = init_conntrack(net, tmpl, &tuple, l3proto, l4proto, 728 skb, dataoff); 729 if (!h) 730 return NULL; 731 if (IS_ERR(h)) 732 return (void *)h; 733 } 734 ct = nf_ct_tuplehash_to_ctrack(h); 735 736 /* It exists; we have (non-exclusive) reference. */ 737 if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY) { 738 *ctinfo = IP_CT_ESTABLISHED + IP_CT_IS_REPLY; 739 /* Please set reply bit if this packet OK */ 740 *set_reply = 1; 741 } else { 742 /* Once we've had two way comms, always ESTABLISHED. */ 743 if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status)) { 744 pr_debug("nf_conntrack_in: normal packet for %p\n", ct); 745 *ctinfo = IP_CT_ESTABLISHED; 746 } else if (test_bit(IPS_EXPECTED_BIT, &ct->status)) { 747 pr_debug("nf_conntrack_in: related packet for %p\n", 748 ct); 749 *ctinfo = IP_CT_RELATED; 750 } else { 751 pr_debug("nf_conntrack_in: new packet for %p\n", ct); 752 *ctinfo = IP_CT_NEW; 753 } 754 *set_reply = 0; 755 } 756 skb->nfct = &ct->ct_general; 757 skb->nfctinfo = *ctinfo; 758 return ct; 759} 760 761unsigned int 762nf_conntrack_in(struct net *net, u_int8_t pf, unsigned int hooknum, 763 struct sk_buff *skb) 764{ 765 struct nf_conn *ct, *tmpl = NULL; 766 enum ip_conntrack_info ctinfo; 767 struct nf_conntrack_l3proto *l3proto; 768 struct nf_conntrack_l4proto *l4proto; 769 unsigned int dataoff; 770 u_int8_t protonum; 771 int set_reply = 0; 772 int ret; 773 774 if (skb->nfct) { 775 /* Previously seen (loopback or untracked)? Ignore. */ 776 tmpl = (struct nf_conn *)skb->nfct; 777 if (!nf_ct_is_template(tmpl)) { 778 NF_CT_STAT_INC_ATOMIC(net, ignore); 779 return NF_ACCEPT; 780 } 781 skb->nfct = NULL; 782 } 783 784 /* rcu_read_lock()ed by nf_hook_slow */ 785 l3proto = __nf_ct_l3proto_find(pf); 786 ret = l3proto->get_l4proto(skb, skb_network_offset(skb), 787 &dataoff, &protonum); 788 if (ret <= 0) { 789 pr_debug("not prepared to track yet or error occured\n"); 790 NF_CT_STAT_INC_ATOMIC(net, error); 791 NF_CT_STAT_INC_ATOMIC(net, invalid); 792 ret = -ret; 793 goto out; 794 } 795 796 l4proto = __nf_ct_l4proto_find(pf, protonum); 797 798 /* It may be an special packet, error, unclean... 799 * inverse of the return code tells to the netfilter 800 * core what to do with the packet. */ 801 if (l4proto->error != NULL) { 802 ret = l4proto->error(net, tmpl, skb, dataoff, &ctinfo, 803 pf, hooknum); 804 if (ret <= 0) { 805 NF_CT_STAT_INC_ATOMIC(net, error); 806 NF_CT_STAT_INC_ATOMIC(net, invalid); 807 ret = -ret; 808 goto out; 809 } 810 } 811 812 ct = resolve_normal_ct(net, tmpl, skb, dataoff, pf, protonum, 813 l3proto, l4proto, &set_reply, &ctinfo); 814 if (!ct) { 815 /* Not valid part of a connection */ 816 NF_CT_STAT_INC_ATOMIC(net, invalid); 817 ret = NF_ACCEPT; 818 goto out; 819 } 820 821 if (IS_ERR(ct)) { 822 /* Too stressed to deal. */ 823 NF_CT_STAT_INC_ATOMIC(net, drop); 824 ret = NF_DROP; 825 goto out; 826 } 827 828 NF_CT_ASSERT(skb->nfct); 829 830 ret = l4proto->packet(ct, skb, dataoff, ctinfo, pf, hooknum); 831 if (ret <= 0) { 832 /* Invalid: inverse of the return code tells 833 * the netfilter core what to do */ 834 pr_debug("nf_conntrack_in: Can't track with proto module\n"); 835 nf_conntrack_put(skb->nfct); 836 skb->nfct = NULL; 837 NF_CT_STAT_INC_ATOMIC(net, invalid); 838 if (ret == -NF_DROP) 839 NF_CT_STAT_INC_ATOMIC(net, drop); 840 ret = -ret; 841 goto out; 842 } 843 844 if (set_reply && !test_and_set_bit(IPS_SEEN_REPLY_BIT, &ct->status)) 845 nf_conntrack_event_cache(IPCT_REPLY, ct); 846out: 847 if (tmpl) 848 nf_ct_put(tmpl); 849 850 return ret; 851} 852EXPORT_SYMBOL_GPL(nf_conntrack_in); 853 854bool nf_ct_invert_tuplepr(struct nf_conntrack_tuple *inverse, 855 const struct nf_conntrack_tuple *orig) 856{ 857 bool ret; 858 859 rcu_read_lock(); 860 ret = nf_ct_invert_tuple(inverse, orig, 861 __nf_ct_l3proto_find(orig->src.l3num), 862 __nf_ct_l4proto_find(orig->src.l3num, 863 orig->dst.protonum)); 864 rcu_read_unlock(); 865 return ret; 866} 867EXPORT_SYMBOL_GPL(nf_ct_invert_tuplepr); 868 869/* Alter reply tuple (maybe alter helper). This is for NAT, and is 870 implicitly racy: see __nf_conntrack_confirm */ 871void nf_conntrack_alter_reply(struct nf_conn *ct, 872 const struct nf_conntrack_tuple *newreply) 873{ 874 struct nf_conn_help *help = nfct_help(ct); 875 876 /* Should be unconfirmed, so not in hash table yet */ 877 NF_CT_ASSERT(!nf_ct_is_confirmed(ct)); 878 879 pr_debug("Altering reply tuple of %p to ", ct); 880 nf_ct_dump_tuple(newreply); 881 882 ct->tuplehash[IP_CT_DIR_REPLY].tuple = *newreply; 883 if (ct->master || (help && !hlist_empty(&help->expectations))) 884 return; 885 886 rcu_read_lock(); 887 __nf_ct_try_assign_helper(ct, NULL, GFP_ATOMIC); 888 rcu_read_unlock(); 889} 890EXPORT_SYMBOL_GPL(nf_conntrack_alter_reply); 891 892/* Refresh conntrack for this many jiffies and do accounting if do_acct is 1 */ 893void __nf_ct_refresh_acct(struct nf_conn *ct, 894 enum ip_conntrack_info ctinfo, 895 const struct sk_buff *skb, 896 unsigned long extra_jiffies, 897 int do_acct) 898{ 899 NF_CT_ASSERT(ct->timeout.data == (unsigned long)ct); 900 NF_CT_ASSERT(skb); 901 902 /* Only update if this is not a fixed timeout */ 903 if (test_bit(IPS_FIXED_TIMEOUT_BIT, &ct->status)) 904 goto acct; 905 906 /* If not in hash table, timer will not be active yet */ 907 if (!nf_ct_is_confirmed(ct)) { 908 ct->timeout.expires = extra_jiffies; 909 } else { 910 unsigned long newtime = jiffies + extra_jiffies; 911 912 /* Only update the timeout if the new timeout is at least 913 HZ jiffies from the old timeout. Need del_timer for race 914 avoidance (may already be dying). */ 915 if (newtime - ct->timeout.expires >= HZ) 916 mod_timer_pending(&ct->timeout, newtime); 917 } 918 919acct: 920 if (do_acct) { 921 struct nf_conn_counter *acct; 922 923 acct = nf_conn_acct_find(ct); 924 if (acct) { 925 spin_lock_bh(&ct->lock); 926 acct[CTINFO2DIR(ctinfo)].packets++; 927 acct[CTINFO2DIR(ctinfo)].bytes += 928 skb->len - skb_network_offset(skb); 929 spin_unlock_bh(&ct->lock); 930 } 931 } 932} 933EXPORT_SYMBOL_GPL(__nf_ct_refresh_acct); 934 935bool __nf_ct_kill_acct(struct nf_conn *ct, 936 enum ip_conntrack_info ctinfo, 937 const struct sk_buff *skb, 938 int do_acct) 939{ 940 if (do_acct) { 941 struct nf_conn_counter *acct; 942 943 acct = nf_conn_acct_find(ct); 944 if (acct) { 945 spin_lock_bh(&ct->lock); 946 acct[CTINFO2DIR(ctinfo)].packets++; 947 acct[CTINFO2DIR(ctinfo)].bytes += 948 skb->len - skb_network_offset(skb); 949 spin_unlock_bh(&ct->lock); 950 } 951 } 952 953 if (del_timer(&ct->timeout)) { 954 ct->timeout.function((unsigned long)ct); 955 return true; 956 } 957 return false; 958} 959EXPORT_SYMBOL_GPL(__nf_ct_kill_acct); 960 961#if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE) 962 963#include <linux/netfilter/nfnetlink.h> 964#include <linux/netfilter/nfnetlink_conntrack.h> 965#include <linux/mutex.h> 966 967/* Generic function for tcp/udp/sctp/dccp and alike. This needs to be 968 * in ip_conntrack_core, since we don't want the protocols to autoload 969 * or depend on ctnetlink */ 970int nf_ct_port_tuple_to_nlattr(struct sk_buff *skb, 971 const struct nf_conntrack_tuple *tuple) 972{ 973 NLA_PUT_BE16(skb, CTA_PROTO_SRC_PORT, tuple->src.u.tcp.port); 974 NLA_PUT_BE16(skb, CTA_PROTO_DST_PORT, tuple->dst.u.tcp.port); 975 return 0; 976 977nla_put_failure: 978 return -1; 979} 980EXPORT_SYMBOL_GPL(nf_ct_port_tuple_to_nlattr); 981 982const struct nla_policy nf_ct_port_nla_policy[CTA_PROTO_MAX+1] = { 983 [CTA_PROTO_SRC_PORT] = { .type = NLA_U16 }, 984 [CTA_PROTO_DST_PORT] = { .type = NLA_U16 }, 985}; 986EXPORT_SYMBOL_GPL(nf_ct_port_nla_policy); 987 988int nf_ct_port_nlattr_to_tuple(struct nlattr *tb[], 989 struct nf_conntrack_tuple *t) 990{ 991 if (!tb[CTA_PROTO_SRC_PORT] || !tb[CTA_PROTO_DST_PORT]) 992 return -EINVAL; 993 994 t->src.u.tcp.port = nla_get_be16(tb[CTA_PROTO_SRC_PORT]); 995 t->dst.u.tcp.port = nla_get_be16(tb[CTA_PROTO_DST_PORT]); 996 997 return 0; 998} 999EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_to_tuple); 1000 1001int nf_ct_port_nlattr_tuple_size(void) 1002{ 1003 return nla_policy_len(nf_ct_port_nla_policy, CTA_PROTO_MAX + 1); 1004} 1005EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_tuple_size); 1006#endif 1007 1008/* Used by ipt_REJECT and ip6t_REJECT. */ 1009static void nf_conntrack_attach(struct sk_buff *nskb, struct sk_buff *skb) 1010{ 1011 struct nf_conn *ct; 1012 enum ip_conntrack_info ctinfo; 1013 1014 /* This ICMP is in reverse direction to the packet which caused it */ 1015 ct = nf_ct_get(skb, &ctinfo); 1016 if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL) 1017 ctinfo = IP_CT_RELATED + IP_CT_IS_REPLY; 1018 else 1019 ctinfo = IP_CT_RELATED; 1020 1021 /* Attach to new skbuff, and increment count */ 1022 nskb->nfct = &ct->ct_general; 1023 nskb->nfctinfo = ctinfo; 1024 nf_conntrack_get(nskb->nfct); 1025} 1026 1027/* Bring out ya dead! */ 1028static struct nf_conn * 1029get_next_corpse(struct net *net, int (*iter)(struct nf_conn *i, void *data), 1030 void *data, unsigned int *bucket) 1031{ 1032 struct nf_conntrack_tuple_hash *h; 1033 struct nf_conn *ct; 1034 struct hlist_nulls_node *n; 1035 1036 spin_lock_bh(&nf_conntrack_lock); 1037 for (; *bucket < net->ct.htable_size; (*bucket)++) { 1038 hlist_nulls_for_each_entry(h, n, &net->ct.hash[*bucket], hnnode) { 1039 ct = nf_ct_tuplehash_to_ctrack(h); 1040 if (iter(ct, data)) 1041 goto found; 1042 } 1043 } 1044 hlist_nulls_for_each_entry(h, n, &net->ct.unconfirmed, hnnode) { 1045 ct = nf_ct_tuplehash_to_ctrack(h); 1046 if (iter(ct, data)) 1047 set_bit(IPS_DYING_BIT, &ct->status); 1048 } 1049 spin_unlock_bh(&nf_conntrack_lock); 1050 return NULL; 1051found: 1052 atomic_inc(&ct->ct_general.use); 1053 spin_unlock_bh(&nf_conntrack_lock); 1054 return ct; 1055} 1056 1057void nf_ct_iterate_cleanup(struct net *net, 1058 int (*iter)(struct nf_conn *i, void *data), 1059 void *data) 1060{ 1061 struct nf_conn *ct; 1062 unsigned int bucket = 0; 1063 1064 while ((ct = get_next_corpse(net, iter, data, &bucket)) != NULL) { 1065 /* Time to push up daises... */ 1066 if (del_timer(&ct->timeout)) 1067 death_by_timeout((unsigned long)ct); 1068 /* ... else the timer will get him soon. */ 1069 1070 nf_ct_put(ct); 1071 } 1072} 1073EXPORT_SYMBOL_GPL(nf_ct_iterate_cleanup); 1074 1075struct __nf_ct_flush_report { 1076 u32 pid; 1077 int report; 1078}; 1079 1080static int kill_report(struct nf_conn *i, void *data) 1081{ 1082 struct __nf_ct_flush_report *fr = (struct __nf_ct_flush_report *)data; 1083 1084 /* If we fail to deliver the event, death_by_timeout() will retry */ 1085 if (nf_conntrack_event_report(IPCT_DESTROY, i, 1086 fr->pid, fr->report) < 0) 1087 return 1; 1088 1089 /* Avoid the delivery of the destroy event in death_by_timeout(). */ 1090 set_bit(IPS_DYING_BIT, &i->status); 1091 return 1; 1092} 1093 1094static int kill_all(struct nf_conn *i, void *data) 1095{ 1096 return 1; 1097} 1098 1099void nf_ct_free_hashtable(void *hash, int vmalloced, unsigned int size) 1100{ 1101 if (vmalloced) 1102 vfree(hash); 1103 else 1104 free_pages((unsigned long)hash, 1105 get_order(sizeof(struct hlist_head) * size)); 1106} 1107EXPORT_SYMBOL_GPL(nf_ct_free_hashtable); 1108 1109void nf_conntrack_flush_report(struct net *net, u32 pid, int report) 1110{ 1111 struct __nf_ct_flush_report fr = { 1112 .pid = pid, 1113 .report = report, 1114 }; 1115 nf_ct_iterate_cleanup(net, kill_report, &fr); 1116} 1117EXPORT_SYMBOL_GPL(nf_conntrack_flush_report); 1118 1119static void nf_ct_release_dying_list(struct net *net) 1120{ 1121 struct nf_conntrack_tuple_hash *h; 1122 struct nf_conn *ct; 1123 struct hlist_nulls_node *n; 1124 1125 spin_lock_bh(&nf_conntrack_lock); 1126 hlist_nulls_for_each_entry(h, n, &net->ct.dying, hnnode) { 1127 ct = nf_ct_tuplehash_to_ctrack(h); 1128 /* never fails to remove them, no listeners at this point */ 1129 nf_ct_kill(ct); 1130 } 1131 spin_unlock_bh(&nf_conntrack_lock); 1132} 1133 1134static void nf_conntrack_cleanup_init_net(void) 1135{ 1136 /* wait until all references to nf_conntrack_untracked are dropped */ 1137 while (atomic_read(&nf_conntrack_untracked.ct_general.use) > 1) 1138 schedule(); 1139 1140 nf_conntrack_helper_fini(); 1141 nf_conntrack_proto_fini(); 1142} 1143 1144static void nf_conntrack_cleanup_net(struct net *net) 1145{ 1146 i_see_dead_people: 1147 nf_ct_iterate_cleanup(net, kill_all, NULL); 1148 nf_ct_release_dying_list(net); 1149 if (atomic_read(&net->ct.count) != 0) { 1150 schedule(); 1151 goto i_see_dead_people; 1152 } 1153 1154 nf_ct_free_hashtable(net->ct.hash, net->ct.hash_vmalloc, 1155 net->ct.htable_size); 1156 nf_conntrack_ecache_fini(net); 1157 nf_conntrack_acct_fini(net); 1158 nf_conntrack_expect_fini(net); 1159 kmem_cache_destroy(net->ct.nf_conntrack_cachep); 1160 kfree(net->ct.slabname); 1161 free_percpu(net->ct.stat); 1162} 1163 1164/* Mishearing the voices in his head, our hero wonders how he's 1165 supposed to kill the mall. */ 1166void nf_conntrack_cleanup(struct net *net) 1167{ 1168 if (net_eq(net, &init_net)) 1169 rcu_assign_pointer(ip_ct_attach, NULL); 1170 1171 /* This makes sure all current packets have passed through 1172 netfilter framework. Roll on, two-stage module 1173 delete... */ 1174 synchronize_net(); 1175 1176 nf_conntrack_cleanup_net(net); 1177 1178 if (net_eq(net, &init_net)) { 1179 rcu_assign_pointer(nf_ct_destroy, NULL); 1180 nf_conntrack_cleanup_init_net(); 1181 } 1182} 1183 1184void *nf_ct_alloc_hashtable(unsigned int *sizep, int *vmalloced, int nulls) 1185{ 1186 struct hlist_nulls_head *hash; 1187 unsigned int nr_slots, i; 1188 size_t sz; 1189 1190 *vmalloced = 0; 1191 1192 BUILD_BUG_ON(sizeof(struct hlist_nulls_head) != sizeof(struct hlist_head)); 1193 nr_slots = *sizep = roundup(*sizep, PAGE_SIZE / sizeof(struct hlist_nulls_head)); 1194 sz = nr_slots * sizeof(struct hlist_nulls_head); 1195 hash = (void *)__get_free_pages(GFP_KERNEL | __GFP_NOWARN | __GFP_ZERO, 1196 get_order(sz)); 1197 if (!hash) { 1198 *vmalloced = 1; 1199 printk(KERN_WARNING "nf_conntrack: falling back to vmalloc.\n"); 1200 hash = __vmalloc(sz, GFP_KERNEL | __GFP_ZERO, PAGE_KERNEL); 1201 } 1202 1203 if (hash && nulls) 1204 for (i = 0; i < nr_slots; i++) 1205 INIT_HLIST_NULLS_HEAD(&hash[i], i); 1206 1207 return hash; 1208} 1209EXPORT_SYMBOL_GPL(nf_ct_alloc_hashtable); 1210 1211int nf_conntrack_set_hashsize(const char *val, struct kernel_param *kp) 1212{ 1213 int i, bucket, vmalloced, old_vmalloced; 1214 unsigned int hashsize, old_size; 1215 struct hlist_nulls_head *hash, *old_hash; 1216 struct nf_conntrack_tuple_hash *h; 1217 1218 if (current->nsproxy->net_ns != &init_net) 1219 return -EOPNOTSUPP; 1220 1221 /* On boot, we can set this without any fancy locking. */ 1222 if (!nf_conntrack_htable_size) 1223 return param_set_uint(val, kp); 1224 1225 hashsize = simple_strtoul(val, NULL, 0); 1226 if (!hashsize) 1227 return -EINVAL; 1228 1229 hash = nf_ct_alloc_hashtable(&hashsize, &vmalloced, 1); 1230 if (!hash) 1231 return -ENOMEM; 1232 1233 /* Lookups in the old hash might happen in parallel, which means we 1234 * might get false negatives during connection lookup. New connections 1235 * created because of a false negative won't make it into the hash 1236 * though since that required taking the lock. 1237 */ 1238 spin_lock_bh(&nf_conntrack_lock); 1239 for (i = 0; i < init_net.ct.htable_size; i++) { 1240 while (!hlist_nulls_empty(&init_net.ct.hash[i])) { 1241 h = hlist_nulls_entry(init_net.ct.hash[i].first, 1242 struct nf_conntrack_tuple_hash, hnnode); 1243 hlist_nulls_del_rcu(&h->hnnode); 1244 bucket = __hash_conntrack(&h->tuple, hashsize, 1245 nf_conntrack_hash_rnd); 1246 hlist_nulls_add_head_rcu(&h->hnnode, &hash[bucket]); 1247 } 1248 } 1249 old_size = init_net.ct.htable_size; 1250 old_vmalloced = init_net.ct.hash_vmalloc; 1251 old_hash = init_net.ct.hash; 1252 1253 init_net.ct.htable_size = nf_conntrack_htable_size = hashsize; 1254 init_net.ct.hash_vmalloc = vmalloced; 1255 init_net.ct.hash = hash; 1256 spin_unlock_bh(&nf_conntrack_lock); 1257 1258 nf_ct_free_hashtable(old_hash, old_vmalloced, old_size); 1259 return 0; 1260} 1261EXPORT_SYMBOL_GPL(nf_conntrack_set_hashsize); 1262 1263module_param_call(hashsize, nf_conntrack_set_hashsize, param_get_uint, 1264 &nf_conntrack_htable_size, 0600); 1265 1266static int nf_conntrack_init_init_net(void) 1267{ 1268 int max_factor = 8; 1269 int ret; 1270 1271 /* Idea from tcp.c: use 1/16384 of memory. On i386: 32MB 1272 * machine has 512 buckets. >= 1GB machines have 16384 buckets. */ 1273 if (!nf_conntrack_htable_size) { 1274 nf_conntrack_htable_size 1275 = (((totalram_pages << PAGE_SHIFT) / 16384) 1276 / sizeof(struct hlist_head)); 1277 if (totalram_pages > (1024 * 1024 * 1024 / PAGE_SIZE)) 1278 nf_conntrack_htable_size = 16384; 1279 if (nf_conntrack_htable_size < 32) 1280 nf_conntrack_htable_size = 32; 1281 1282 /* Use a max. factor of four by default to get the same max as 1283 * with the old struct list_heads. When a table size is given 1284 * we use the old value of 8 to avoid reducing the max. 1285 * entries. */ 1286 max_factor = 4; 1287 } 1288 nf_conntrack_max = max_factor * nf_conntrack_htable_size; 1289 1290 printk("nf_conntrack version %s (%u buckets, %d max)\n", 1291 NF_CONNTRACK_VERSION, nf_conntrack_htable_size, 1292 nf_conntrack_max); 1293 1294 ret = nf_conntrack_proto_init(); 1295 if (ret < 0) 1296 goto err_proto; 1297 1298 ret = nf_conntrack_helper_init(); 1299 if (ret < 0) 1300 goto err_helper; 1301 1302 /* Set up fake conntrack: to never be deleted, not in any hashes */ 1303#ifdef CONFIG_NET_NS 1304 nf_conntrack_untracked.ct_net = &init_net; 1305#endif 1306 atomic_set(&nf_conntrack_untracked.ct_general.use, 1); 1307 /* - and look it like as a confirmed connection */ 1308 set_bit(IPS_CONFIRMED_BIT, &nf_conntrack_untracked.status); 1309 1310 return 0; 1311 1312err_helper: 1313 nf_conntrack_proto_fini(); 1314err_proto: 1315 return ret; 1316} 1317 1318/* 1319 * We need to use special "null" values, not used in hash table 1320 */ 1321#define UNCONFIRMED_NULLS_VAL ((1<<30)+0) 1322#define DYING_NULLS_VAL ((1<<30)+1) 1323 1324static int nf_conntrack_init_net(struct net *net) 1325{ 1326 int ret; 1327 1328 atomic_set(&net->ct.count, 0); 1329 INIT_HLIST_NULLS_HEAD(&net->ct.unconfirmed, UNCONFIRMED_NULLS_VAL); 1330 INIT_HLIST_NULLS_HEAD(&net->ct.dying, DYING_NULLS_VAL); 1331 net->ct.stat = alloc_percpu(struct ip_conntrack_stat); 1332 if (!net->ct.stat) { 1333 ret = -ENOMEM; 1334 goto err_stat; 1335 } 1336 1337 net->ct.slabname = kasprintf(GFP_KERNEL, "nf_conntrack_%p", net); 1338 if (!net->ct.slabname) { 1339 ret = -ENOMEM; 1340 goto err_slabname; 1341 } 1342 1343 net->ct.nf_conntrack_cachep = kmem_cache_create(net->ct.slabname, 1344 sizeof(struct nf_conn), 0, 1345 SLAB_DESTROY_BY_RCU, NULL); 1346 if (!net->ct.nf_conntrack_cachep) { 1347 printk(KERN_ERR "Unable to create nf_conn slab cache\n"); 1348 ret = -ENOMEM; 1349 goto err_cache; 1350 } 1351 1352 net->ct.htable_size = nf_conntrack_htable_size; 1353 net->ct.hash = nf_ct_alloc_hashtable(&net->ct.htable_size, 1354 &net->ct.hash_vmalloc, 1); 1355 if (!net->ct.hash) { 1356 ret = -ENOMEM; 1357 printk(KERN_ERR "Unable to create nf_conntrack_hash\n"); 1358 goto err_hash; 1359 } 1360 ret = nf_conntrack_expect_init(net); 1361 if (ret < 0) 1362 goto err_expect; 1363 ret = nf_conntrack_acct_init(net); 1364 if (ret < 0) 1365 goto err_acct; 1366 ret = nf_conntrack_ecache_init(net); 1367 if (ret < 0) 1368 goto err_ecache; 1369 1370 return 0; 1371 1372err_ecache: 1373 nf_conntrack_acct_fini(net); 1374err_acct: 1375 nf_conntrack_expect_fini(net); 1376err_expect: 1377 nf_ct_free_hashtable(net->ct.hash, net->ct.hash_vmalloc, 1378 net->ct.htable_size); 1379err_hash: 1380 kmem_cache_destroy(net->ct.nf_conntrack_cachep); 1381err_cache: 1382 kfree(net->ct.slabname); 1383err_slabname: 1384 free_percpu(net->ct.stat); 1385err_stat: 1386 return ret; 1387} 1388 1389s16 (*nf_ct_nat_offset)(const struct nf_conn *ct, 1390 enum ip_conntrack_dir dir, 1391 u32 seq); 1392EXPORT_SYMBOL_GPL(nf_ct_nat_offset); 1393 1394int nf_conntrack_init(struct net *net) 1395{ 1396 int ret; 1397 1398 if (net_eq(net, &init_net)) { 1399 ret = nf_conntrack_init_init_net(); 1400 if (ret < 0) 1401 goto out_init_net; 1402 } 1403 ret = nf_conntrack_init_net(net); 1404 if (ret < 0) 1405 goto out_net; 1406 1407 if (net_eq(net, &init_net)) { 1408 /* For use by REJECT target */ 1409 rcu_assign_pointer(ip_ct_attach, nf_conntrack_attach); 1410 rcu_assign_pointer(nf_ct_destroy, destroy_conntrack); 1411 1412 /* Howto get NAT offsets */ 1413 rcu_assign_pointer(nf_ct_nat_offset, NULL); 1414 } 1415 return 0; 1416 1417out_net: 1418 if (net_eq(net, &init_net)) 1419 nf_conntrack_cleanup_init_net(); 1420out_init_net: 1421 return ret; 1422} 1423